Approximately 25 million persons each year in the United States are tested for antibody to human immunodeficiency virus (HIV). Publicly funded counseling and testing (CT) programs conduct approximately 2.5 million of these tests each year. CT can have important prevention benefits; however, in 1995, 25% of persons testing HIV-positive and 33% of persons testing HIV-negative at publicly funded clinics did not return for their test results. Rapid tests to detect HIV antibody can be performed in an average of 10 minutes, enabling health-care providers to supply definitive negative and preliminary positive results to patients at the time of testing, potentially increasing the overall effectiveness of CT. In comparison, results from enzyme immunoassays (EIAs) currently used for HIV screening often are not available for 1-2 weeks. To quantify the potential advantages and disadvantages of using rapid tests for CT, CDC estimated the potential impact on the number of persons who would learn their HIV-test results. This report summarizes the results of the analysis and provides the basis for changing the Public Health Service (PHS) recommendations for providing HIV-test results.